Tilting chair



NOV. 25, 1952 w, VAN QSSELEN 2619,153

TILTING CHAIR Filed 001:. 2, 1950 Patented Nov. 25, 1952 TIL'IING CHAIR Willem van, Osselen, Huis ter Heide (Utrecht), Netherlands, assignor to Gispens Fabriekvoor Metaalbewerking N. V. Rotterdam, Netherlands Application October 2, 1950, Serial No. 187,878 In the Netherlands February 22; 1950 1 Claim. 1

My present invention relates to chairs of the type wherein the seat is pivotally mounted, at or close to its front edge, upon a base member and adapted to be held by a spring member in normal, substantially horizontal position, said spring member being loaded when the seat is depressed so as to swing about its pivot.

It is desirable that chairs of this kind be of a character such that the seat is held in normal, i. e. unoccupied, substantially horizontal position as long as the person using the chair is sitting on the same in the normal and usual way, but that it is readily and smoothly tilted or tipped against the action of the spring member when said person shifts his center of gravity rearwards to lean back, so that the comfort of the person is best provided for.

In accordance with the present invention a ohair, comprising in combination a base member, a seat pivoted to the base member about a cross axis close to its front edge, and a spring member tending to hold. the seat substantially horizontal, is provided with at least one arm whose lower end is rotatably mounted upon the base member about an axis in parallel relation with the pivot of the seat and whose upper end is urged by the spring member into supporting engagement with the seat so as to assume a position wherein it has only a slight rearward deviation from the vertical when the seat is substantially horizontal, an abutment being provided preventng the arm from being moved by said spring member in forward direotion beyond said position.

In order that my inventon may be more ully understood by those skilled in the art, I shall now proceed to describe a preferred embodiment thereof with referenoe to the annexed drawng, in which:

Fig. 1 is a plan view of the base member of the char,

Fig. 2 is a side elevational view of part of the base member and the seat, and

Fig. 3 is a somewhat diagrammatio side view, on a reduced scale, of the complete chair with a rearwardl leaning person sitting thereon.

As shown, the chair comprises a base member 4 supported by our casters 5 and accommodating a central, vertical spindle 6. Rigidly seoured to the top end of spindle 6 is a cross-pece l, to whose ends are rigidly secured two parallel supporting bars 8, 9 of equal lengths and extending in forward direotion. The oiset ends of said bars are interoonneoted by a cross rod Hl rotatably supported in suitable bearings thereof.

Bod 10, in combnation with two rearwardly extending bars Il, I2 rigidly secured thereto, constitute the tiltable frame for supportng the seat I3 and the back [4 of the char.

Hinged to the bars 8, 9 in points spaced a small distance from the cross-piece 'l are arms [5, 16 adapted to swing about aligned axes parallel with rod |0. Each of said arms is provided, in addition to aroller I5a (I6a) pivoted thereto near its upper end and rotatable relative thereto about an axis parallel with rod |0, with a hook I5b (l6b) at its upper end and, intermediate its lower end and its roller, with a lug (I Go) engaged by one end of a coiled spring I'! (18), the other end of which is secured to a screw I 9 (20) extending through a hole of bar 8 (9). The projecting end of said screw is in threaded engagement with a nut 2! (22) having a milled head.

By means of nuts 2 I, 22 the sprngs Il, l8 can be tensioned so that the arms I5, I6, through their rollers 15a, 16a, are urged into engagement with the lower edges of bars II, 12 and thereby tend to swing the seat upwards about its pivot Ill. I-Iowever, when the seat assumes its normal, substantially horizontal position the hooks 1%, [62) of said arms engage abutments Ha, I2a provided on bars II, I2, thus positively preventing the seat from swinging upwards beyond normal position.

In Fig. 2, the seat in normal position is shown in full lines. If, now, a person sits down in the chair in the usual way, the seat remains substantially horizontal, provided the springs IT, IS, have been suitably tensioned in accordance with the weight of said person. Sinoe, in this position of the seat, the arms [5, [6 are almost vertcal, it is obvious that the pull exerted b said springs on said arms need only be comparatively slight. However, if said person shifts his center of gravity rearwards by leaning back, the load on the springs will be ncreased untl the resisting moment exerted on the arms l5, !6 by the springs equals that exerted by the load, whereupon any further rearward displacement of said center of gravity will cause the seat to tilt and to reach another position of equilibrium (as shown in dotted lines in Fig. 2), whereby the arms l5, I6 are swung backwards and the springs [1, [3 are further tensioned. Owing to said swinging movement of arms 15, 16, the increase of the moment exerted on the arms l5, 15 by the loa-d on the seat is comparatively very rapid, so that the tilting movement of the seat is smooth and comfortable. During this tilting 3 movement the front edge of the seat remains on the same level, thus allowing the person leanng back in the chair to comfortabiy rest wth hs eet on the floor as shown in Fig. 3.

If the person thereafter resumes normal position, the seat w1l immediately fellow.

What I claim is:

A tilting chair comprsng a base member, a seat having a front edge and pvotally mounted adjacent said front edge on said base member for swnging about a horizontal cross axis, a back rest rigidly secured to said seat, at least one upwardly directed arm pvotally mounted at its lower end on sad base member for swingng about an axs spaced rearwardly from said front edge and in a vertical plane dsposed at right ang1es to said horzontal cross axis, a spring member interconnecting sad base member wth said arm to resilently urge the latter in the direction towards said front edge of .the seat,

4 means lmting the spring urged movement of said arm to a position in which said arm has only a slight rearward deviaton from the vertcal, and means on sad arm operatve to support said seat during the rearward swingng movement of said arm, the last mentoned means beng positoned on sad arm so that said seat is substantially horzontal when said arm is in said limted postion.

WILLEM VAN OSSELEN.

REFERENCES CITED The iollowng references are of record in the file of ths patent:

UNI'I'ED S'IA'IES PATENTS Number Name Date 240,888 Chchester May 3, 1881 2,447,601 Sengpel Aug. 24, 1948 

